The present invention relates to display systems, in particular, to display systems presenting real time high-definition images over a large viewing area viewable at short distances and wide angle.
The prior art in the field of fiber optic display systems can be partitioned into two distinct groups: fixed content, and real time displays. The fixed content fiber optic displays encompass the devices whose image content is predetermined prior to their operation, and either does not change or has a repeating cycle during operation. These devices include a variety of lighted signs, decorative devices, and many others. These fixed content displays are not suitable or practical to be used for real time images.
Real time fiber optic displays encompass a device whose image content is generated at the time of its operation and is changed at a suitable rate to produce an appearance of a continuous image. The fiber optic displays comprising the current art can be characterized as devices based on generation of images by low or lower density fiber at the viewable surface in relation to high or higher density fiber at the image source. Such devices are referred to hereinafter as low to high density (LHD) devices.
In general, an LHD device is characterized by a light source generating an image or images displayed at a viewing surface where fiber density is lower in comparison to the fiber density at the light source. In other words, these devices display an image on a viewing surface by expanding fiber optic bundles from a high density arrangement at image acquisition or at the image source to a lesser density arrangement at the image display or viewing surface.
The LHD fiber optic devices are suitable as image display systems, but they suffer from a number of deficiencies. The primary deficiency of these systems is that image quality of the displayed image cannot exceed the image quality of the image being generated by the source. For example, an image being generated by pixels transmitting red, green, and blue (RGB) light at 1280xc3x971024 resolution, which is equivalent to that of a contemporary computer CRT monitor, onto a 2560xc3x972048 fiber bundle will produce only 1280xc3x971024 images distributed over a surface area that is four times larger.
Another deficiency found in prior art devices is that projection of the image onto high-density fibers can suffer from misalignment between pixels of the projector and the individual fiber strands of the bundle. The misalignment can be generally attributable to gaps between both fibers and pixels, small fiber diameters and pixel size, and projection of the image at a short distance to the fiber. A number of solutions for light to fiber projection are handled by injection of light into the fiber. A number of injection solutions have been established in the art including coating of the fibers with phosphor or other compounds of similar properties. It can be argued that such solutions have not been shown sufficiently practical since the individual components of such techniques, when applied as a whole, present many difficulties. A particular problem is with the tripling of the amount of fiber to deliver an RGB output when coating different strands with each RGB component. This can be compensated by coating the same strands with all RGB components, but at the expense of increase in difficulty of fabrication.
The real time display system of the present invention represents a novel approach to image generation where the image on the viewing area is produced by reduction from the image generating area. Generally, contemporary image-generating devices found in the art function as image enlarging apparatus where the image is increased from the image generating area to the image viewing area. The novel approach of the present invention may be at first seen as counter productive as the goal of image generation is to produce higher quality images over a large surface. Contrary to such initial observation, it will be observed that the real time display system of the present invention is particularly suitable to produce large scale high definition display devices, such as video walls.
It is therefore an object of the present invention to provide a real time display system having a high-density fiber display surface and a low density image generating source.
It is another object of the present invention to provide a real time display system reducing the difficulty of fabrication of a fiber optic display system by eliminating the requirement of assembling the fibers at high densities at the image generating source.
It is another object of the present invention to provide a real time display system utilizing the light vectoring abilities of optic fibers to de-couple the two dimensional geometry of the image display surface from the geometry of the image light sources.
It is still another object of the present invention to provide a real time display system utilizing a two-dimensional viewing surface in combination with other components arranged in a three-dimensional space thereby altering the alignment of those components in relation to the viewable surface.
It is yet another object of the invention to provide a real time display system including a display having small pixel diameters on the viewable surface forming high pixel densities enabling display of high definition images.
The display system of the invention comprises an array of pixels forming a continuous viewable surface. Each pixel is formed by a bundle of one or more optical fibers which vector light to the pixels from one or more light sources. High density of pixels at the viewable surface is achieved by bundling small diameter optical fibers adapted for vectoring light from light sources arranged at a density lower than that of the viewable pixels. The two-dimensional geometry of the viewable surface is de-coupled from the light source which is arranged in a three dimensional space thereby compensating for the difference in densities.